Improved metallic burr



A. T. BOON.

Metallic Burr.

Nb. 40,549. Patented Nov. 10. 1863.-

NITED STATES PATENT OFFIC ALONZ O T. BOON, OF GALESBURG, ILLINOIS.

IMPROVED METALLIC BURR.

Specification forming part of Letters Patent No. 40,549, dated November10, 1863.

To all whom it may concern:

Be it known that I, ALONZO T. BOON, of Galesburg,in the county of Knox,in the State of Illinois, have invented a new and useful Improvement inthe Manufacture of Steel Burrs for Mills of all Descriptions; and I dohereby declare that the following is a full, clear, and exactdescription thereof, reference being had to the accompanying drawings,forming a part of this specification, and of which- Figure 1 is a sideelevation; Fig. 2, a top view of my improved cast-steel mill-burr.

. Similar letters indicate similar parts in each of the drawings,

The nature of my invention consists in manufacturing a metallicgrinding-surface for mills by casting molten .steel in suitable molds,by which I obtain at a comparatively low cost a grinding surt'ace ofextreme hardness, toughness, and durability.

Heretofore grinding-surfaces for mills of various kinds have been madeof cast iron in many ways, but, owing to the difficulty of retaining thetemper of the metal in the process of casting, they have proved to bewanting in durability, wearing out and soon becoming useless. By myimproved mode of casting grinding-plates these defects are overcome, andI am enabled to produce a steel burr of such a quality and temper as toretainits edge much longer than any now in use.

I form the molds for the casting of iron in the manner well known toworkers in metal, and so divided as that they can be quickly and readilydetached from the core, and of such patterns and so corrugated as may bedesired in ,the grinding-surface of the steel plate. Into, these moldsI. pour molten cast-steel, taking great care that it shall be perfectlylimpid, (so limpid as that it shall not adhere to an iron rod dippedtherein,) and then so soon as it hasreceived the formdesired immediatelyopen the molds and chill the casting to obtain the desired temper. Themolds are so formed with air-vents as to permit its free escape as theyare filled and yet prevent the escape of the molten steel.

Great skill and experience is required in order to conduct properly thecasting of such plates, although the process is simple as described. Thesuperior temper and quality of a grinding-surface, A, Fig. 1, thusformed, permits it to be manufactured and used of a comparatively smallthickness, and, therefore, I propose to use it as a facing upon wheelsof cheaper material. I prefer to combine it with wheels or burrs, B, ofcast-iron, by means of bolts or rivets, suitable apertures being formedtherein for this purpose. 1 contemplate, however, any secure mode ofcombining the two for the end required.

What I claim as new in this my invention, and desire to secure byLetters Patent, is

Making the grinding surface of mill-burrs of caststeel in the form of athin circular disk and attaching the same to the face of the iron diskor its equivalent, substantially as de scribed.

ALONZO T. BOON. Witnesses:

WM. SHERWIN RANSOM, J. P. DORMAN.

